Septic tanks – the UK’s secret sewage problem

Septic tanks are not the most glamorous topic...

...But they are definitely the ‘elephant in the room’ when it comes to protecting our waters from nutrient pollution.

What are septic tanks?

There are a vast array of homes that are not linked up to main sewage treatment works. Where properties are located at least 50 metres from a sewer, septic tanks or package treatment plants are the dominant method of sewage disposal.

Septic tanks are essentially underground tanks. Solids sink to the bottom, forming sludge, and liquid flows into a drainage field, where bacteria take out the bad bits as it soaks into the ground. When used and maintained properly these ‘micro-treatment works’ do their job very well.

Why are septic tanks an issue?

It seems quite obvious, but to keep our wild fish and other water life thriving, they need a sewage-free place to live.

Wastewater contains nitrogen and phosphorus from human waste, food, certain soaps and detergents. If a septic tank is not operating correctly, these nutrients are discharged into watercourses. Excess nutrients are bad news for river systems.

There are a variety of reasons why septic systems fail, but one of the most common is poor maintenance. For example, irregular septic tank emptying may cause solids in the tank to block the soakaway and clog the complete system, increasing the risk of an environmentally damaging incident.

Another big issue is regulation around these micro-treatment works. Despite more rigorous regulations being recently introduced for installation of new septic tanks, the vast quantity of unregistered older systems still remain, with their condition and effectiveness largely a mystery.

Rules around septic tanks are also mostly advisory with a lack of top-level ownership around the issue. The absence of a single authority control has led to frequent installation of systems with inadequate drainfield designs, in unsuitable locations and with no common policy covering their registration or maintenance. Systematic inspections are also lacking, currently only discharges of larger systems with specific permits are routinely monitored for discharge quality.

What you can do

To keep our rivers healthy and bursting with life we need your help to keep them sewage-free.

  • If you are a septic tank owner, be responsible & educated.
  • There is some fantastic information around that will answer any questions you have. One of our favourite resources is http://www.callofnature.info/
  • If you know other family and friends with this kind of system, share your knowledge!
  • Report incidents - If you see a suspicious septic tank discharge to your local river, report it! Send us a photograph and a google maps location and we’ll happily take a look.